A. Field of the Invention
The present invention relates to a barrier structure of a plasma display panel and, particularly, to a barrier structure formed on a substrate in order to define a space for discharges.
B. Discussion of Related Art
A typical color PDP (Plasma Display Panel), as shown in FIG. 1, has upper and lower structures. The upper structure, which is viewed the side for better understanding, consists of upper substrate 1, dielectric layer 5 for sustaining surface charges formed during a discharge of the sustain electrodes 3, a protection layer 6, and upper barriers 9. The lower structure consists of lower substrate 2, lower electrodes 4 formed on the lower substrate 2 perpendicular to the sustain electrodes 3, lower barriers 7 formed between the upper and lower substrates 1 and 2 in parallel with the lower electrodes 4, and phosphor 8 coated on the surface of the lower barriers 7.
The space between the upper and lower structures is sealed with inert gas contained therein, forming a discharging area.
Initially, when a high voltage is applied sufficient to cause discharges in all discharging cells on the panel between both ends of the sustain electrodes 3, the charges formed on the surfaces of the barriers 7 and 9 and the dielectric layer 5 are eliminated and charges are thereby distributed uniformly all over the discharging cells. As a result, the inner surface of the discharging area has no charge formation.
In the subsequent addressing step, cells to be discharged are supplied with an address voltage, causing a discharge between the lower electrodes 4 and the sustain electrodes 3 that are energized by a scan voltage, thus forming wall charges on the surface of the protection layer 6.
A sustain voltage is then applied between the sustain electrodes 3 during a sustain period so as to sustain the discharges in the cells having wall charges. Discharges cannot continue in the cells that have no wall charges formed thereon, when sustain voltage is supplied.
However, as shown in FIG. 2, a discharging voltage applied to both ends of transparent electrode lines a and a' out of sustain electrodes 3 causes a cooperative surface discharge in the discharging area. Bus electrode lines b and b' are formed on the transparent electrode lines a and a', respectively, to prevent a voltage drop that may be caused by the resistance of the transparent electrode lines a and a'. Unfortunately, an excessive discharging current generated at this stage can damage the electrodes.